Dino, GHA, or Something Else?

I am having issues with what I thought was hair algae at first then Dino. But now I am confused and not sure what it is.

Background: a few months ago I had a break out of Dino. It was brown snot like substance filled with a ton of air bubbles and looked very much like Dino. I solved the issue by reducing my light some and over feeding to keep my nutrients up.

Next I had GHA start taking hold, so I backed off on the over feeding and found a decent balance until the past couple of weeks.

A few weeks ago something that looked more like GHA but was brown started to take over. I reduced my feedings and nutrients and it got worse. So then I increased my feeding again thinking maybe it was a different kind of Dino because my phosphate bottomed out. But that hasn’t helped either. I have been trying to manually remove it as best I can. But it doesn’t just blow off the rocks like the Dino I had last time. It almost seems like some evil cross between GHA and Dino. If that makes sense.

It seems to be toxic like Dino. I have started losing my herbivore fish. First my lawnmower blenny. Then newly added kole tang. Then it’s replacement 2 spot bristletooth tang. And now my 4 inch fox face is starting to twitch. No signs of disease or stress (except the fox face twitching oddly). Also all of my other fish are doing fine (clowns, pyramid butterfly, fire fish, 2 flasher wrasse, melanurus wrasse). I replaced my carbon yesterday to see if that would help. Also my BTA seems to be perfectly happy and growing, and it is probably the most sensitive thing in my tank.

It’s a 4 foot 150g tank with a sump.

My nitrate and phosphate are high due to excessive feeding, which is a reason I was doubting it was Dino. Also it is probably unrelated but I have seen the small Korelia powerhead start to have calcification on the top of it, and my calcium has dropped significantly in the last 1-2 weeks.

Doesn't look like dinos at all. I don't think the algae is the reason for the fish loss. Do you quarantine your fish additions?

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I have been until the last one the 2 spot bristletooth tang from divers den. There weren’t any signs of illness prior to the deaths. They were swimming and eating fine. No spots or mucus or anything out of the ordinary. They were perfectly fine one minute and dead hours later. And it has exclusively seemed to impact herbivores so far. The only sign of anything off has been the twitch my fox face has developed over the past few days. But he is still eating and doesn’t show any other symptoms that I can see.

I should also mention the first fish to disappear was my lawnmower blenny. He was one of the first fish I got and was a great grazer of the rocks. He wasn’t new. I don’t know exactly when he died I just realized I hadn’t seen him in weeks (before the latest fish additions). He was always a little skittish so it wasn’t abnormal for him to hide some.